Computers have been adapted for a multiplicity of uses, from the storing and manipulation of data, including the performance of complex mathematical operations, to use as a word processor, and as a means of communication for the handicapped.
In this latter field it has been found that autistic people appear to derive great benefit in enhancing their ability to communicate with others, through the medium of a computer, while in the case of the physically handicapped access to a computer keyboard by various assisting devices has vastly enhanced both the ability to communicate, and the capability of accessing other services that a computer can provide.
Examples of such prior art use, primarily of computers, and ways of enhancing access to, and the utilization of devices such as computers can be found in the following listed patents, among others:
U.S. Pat. No. 3,895,185, Ramsey, July 1975
U.S. Pat. No. 4,381,502, Prame, April 1983
U.S. Pat. No. 4,559,598, Goldwasser et al., December 1985
U.S. Pat. No. 4,642,610, Smith, February 1987
U.S. Pat. No. 4,746,913, Volta, May 1988
U.S. Pat. No. 5,051,745, Katz, September 1991
U.K. Patent No. 1,166,441, Lewin et al., October 1969
U.S. Pat. No. 5,220,652, Rowley, June 1993
Ramsey (U.S. '185) provides circuitry for complex dot-dash generation, recognition and organization; requiring two keys or switches to enable their simultaneous use; also a 63-character tree counter is provided.
Alphabetical character access has been simplified by Prame (U.S. '502), requiring the use of two keys; the Goldwasser et al. (U.S. '598) has accessed screened text, by pointing to desired portions of text with a pointer, to effect selection; Smith (U.S. '610) provides two-rate character scanning; Volta (U.S. '913) provides a variable modulated "ability" control; Katz (U.S. '745) teaches a method of string element searching, using hashed text; Rowley (U.S. Pat. No. '652) provides a complex word selection system involving a binary search technique to navigate a vocabulary list requiring four switches in separated relation, or a single, strobing control switch, with associated adverse time requirements both of user and computer. The '652 binary search is based upon presentation as the first word of a binary tree being approximately the middle word of the alphabetical order, regardless of frequency of use of that word. Lewin et al. (U.K. '441) teaches the use of a recording tape deck with a control key and a recording key.
These prior art arrangements are generally relatively slow in operation, and usually require the capability of operating a plurality of keys.
In the matter of hashing text, this may be done mathematically, giving each letter of the alphabet its own unique numerical value, and then summing the total value of a word, which is then input into the computer. In view of the existence of 26 letters in the alphabet, the coding arithmetic is time-consuming, and if carried out mentally, as would be the case for a severely handicapped user, could readily lead to errors. Furthermore, each word constitutes but a single entry, for purposes of carrying out comparisons.